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Joshua Holbrook
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General Information & Atomic Structure:
Physical Properties:
  • Atomic Number: 55
  • Atomic Mass: 132.90545 ± 0.0000002 u
  • Number of protons within the nucleus: 55
  • Number of electrons within the neutral atom: 55
  • Most common isotope: 133Cs
  • Number of neutrons within the nucleus of the most common isotope: 78
  • State of matter at room temperature: Liquid
  • Melting point: 28.44 °C
  • Boiling point: 671 °C
  • Density: 1.93 g·cm−3
  • Abundance in earth’s crust: 0.00019%
Chemical Properties:
Background:
  • Other elements that will react with Cs: O, S, P, F, Cl, Br, I, and At, as well as acids and water (even at temperatures as low as −116 °C!)
  • Compounds that contain Cs: Cesium bromide is used to make radiation detectors and other measuring devices. Cesium carbonate and cesium chloride are used in the brewing of beer.
  • Robert Bunsen and Gustav Kirchhoff first discovered Cs in the mineral water from Dürkheim (Germany) in 1860, however Carl Setterberg was the first to isolate the pure metal
  • The name cesium comes from the Latin word caesius, meaning “sky-blue” (after the bright blue lines in its emission spectrum)
  • The two main uses for Cs are: cesium formate-based drilling fluids for the extractive oil industry, and in atomic clocks

Cesium formate, dissolved or suspended in water, is used as a drilling fluid for drilling deep oil wells. Cesium formate solutions are extremely dense, allowing rock chips and dust to float to the surface from the bottom of a deep well as it is being drilled.

Cesium is also used in atomic clocks to keep time. Cesium-based atomic clocks observe electromagnetic transitions in the hyperfine structure of cesium-133 atoms and use it as a reference point. In 1967, a specific frequency from the emission spectrum of cesium-133 was chosen to be used in the definition of the second by the International System of Units.



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Works Cited:
"Cesium." ChemistryExplained.com. Advameg, Inc., n.d. Web. 23 Dec. 2012.
Gray, Theodore. "Cesium." The Photographic Periodic Table of the Elements. Wolfram Research, n.d. Web. 23 Dec. 2012.
Wikipedia Contributors. "Caesium." Wikipedia. Wikimedia Foundation, 21 Dec. 2012. Web. 23 Dec. 2012.